class_docstr: Group together categories which occurence is less than a specified
  minimum fraction. Coalesced categories get index of one.
code: def __init__(self, minimum_fraction=None):
      self.minimum_fraction = minimum_fraction
  
file_path: auto-sklearn/autosklearn/pipeline/implementations/MinorityCoalescer.py
imports: import numpy
  from scipy import sparse
  from sklearn.base import BaseEstimator, TransformerMixin
label_desc: Use image node_id 1 to create a new MinorityCoalescer object from inherited base classes: BaseEstimator, TransformerMixin with example: obj = MinorityCoalescer(minimum_fraction)